1. Field of the Invention
The present invention relates to sliding-weight operated tools, and more particularly to sliding-weight operated hole boring tools.
2. Background of the Invention
Sliding-weight operated tools have been around for a number of years. U.S. Pat. No. 716,274, issued in 1902, discloses one such tool, which comprises a rod having dual collars, a sliding weight disposed on the rod between the collars, and tool bits disposed on the rod on opposite ends of the rod from the collars. The tool was designed to be used to form holes in masonry, and in operation, one of the tool bits (for example, a hollow cylinder) is placed against the masonry such that the tool extends perpendicularly from the masonry. The sliding weight is then repeatedly and forcefully slid into contact with the collar adjacent the tool bit. The momentum of the weight is transferred to the tool bit at each strike of the collar by the weight, thereby causing the tool bit to penetrate the masonry and form a hole therein.
U.S. Pat. No. 3,050,095 discloses another sliding-weight operated tool, which comprises a hexagonal rod having a tear-drop shaped tool bit on one end thereof, a first collar adjacent the other end, a second collar intermediate the first collar and the tool bit, and a sliding weight disposed on the rod between the two collars. The sliding weight has two handles projecting ourtwardly therefrom, and the tool is described as being useful for boring holes in tree stumps. In operation, the sliding weight is slid upwardly and downwardly between the two collars and when it strikes the second collar, the impact is transmitted to the tool bit, which forms a hole in the tree stump.
U.S. Pat. No. 3,568,657 discloses a tool for breaking rocks, similar to the tool of Pat. No. 716,274, in which various means are provided to remove the sliding weight from the tool.
Yet another sliding-weight operated tool is described in U.S. Pat. No. 4,241,795. In that tool (a "manual jack hammer"), the sliding weight is a rod disposed within a shaft, and strikes a tool bit, a portion of which is elastically retained in the lower end of the shaft.
While it appears that these tools would function well in carrying out the jobs for which they were intended, they are inherently limited by their structure as to the length or depth of holes which they are capable of boring. Also, they would not function well in certain soil conditions.